From patchwork Tue Jan 23 00:27:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 13526735 Received: from mail-pf1-f169.google.com (mail-pf1-f169.google.com [209.85.210.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9C1FC13B792 for ; Tue, 23 Jan 2024 00:46:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970764; cv=none; b=J7PxtjJrJrwH2y3da07FADQqWCM0W0enEDOwrljNixctoz4PXlN1uRmSq2BqLVIcoB5pB72tG+wtH0mGIe4iKKMFIQogx2tK6Y9DBPP/y1UKuPjzwmn/z/vOb2FSVGTBbeqK3QavFCWh3xUiIVecQKNzJKWtucIr04qYjfJ/T9I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970764; c=relaxed/simple; bh=rhiNkfwcsBY8pN0Aj3OX3M7epOQG7vcAhg9hdXLwAek=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=f3TuJ66tW2b8kFepQCzMsTN738jHOcurAco8WLqWUd5k3KVbVrrK/LKW7Z7/dd6VulL8FUC2mD93Tor2K1IDgEcWRKUPBzq8Ap4krtQdcisCNTbhDtNHbea7TAIhi7VsTtJAR684QYQZlHpnrTYY6zqRAF3JKQyLyL26GtzmeCk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=j8KUJJgt; arc=none smtp.client-ip=209.85.210.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="j8KUJJgt" Received: by mail-pf1-f169.google.com with SMTP id d2e1a72fcca58-6dc1f02090fso454405b3a.0 for ; Mon, 22 Jan 2024 16:46:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1705970762; x=1706575562; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=koLuWwEc6R93KvA47iKWZn4p87NyejoVGKhwRpq6uhs=; b=j8KUJJgt1OC46MRP1rTSCjb3ikE3ot4TXw9Tukg8wx7H+83b6ohP4LHJ9UNddjKRl2 fSHxXLpJPJivZGL1FttjKFG88OY1GIfXdbJmN3+4oYrwPx/KuMNiKYcL0usJSbXDhAA/ pNz4tVDi9c8HBow8e9NE5hiv1GNBnowyNm78Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705970762; x=1706575562; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=koLuWwEc6R93KvA47iKWZn4p87NyejoVGKhwRpq6uhs=; b=HGtzf7uTziYJmnAyuUMGKVvO9potrUQLNMOvioy/Frh6EwA/tbHrcEC0bN2hxIFrty nLSqnlQOj88kfhb63TmouT5EBWxU8YYdo2aDS5j3jynX74I6/e4kw4AAWACbTbLLcQLa ijskmd3tcx2VttxBt0TLJqBwGxScMk8ID6iDYLDgcCHZ+NjQ5FV4Y4k2oOvBEIomfvQx CJsxk7qF91G5UfdIS0k0yoYkql3hgccBJ3n8A7ivAPPuqL/8e2AKQ2BxuWWI43nIoGeM o3E+dVtiDq4gu85WO39o8cWBC1NiqV+UWPA4nM8pAPnDSJYZxZuSY9hDsh7FxxxxJlG9 55ow== X-Gm-Message-State: AOJu0YzfOcRVUzi/a7ECFqQxJIXqWyLB4wqC2OX4dDMuh0TnGDauYghu Y0MgHNnCHQjGEGnYWnJ/j//O+yOxG4sZZaKuGEgK/ICkchf67HAyVP6MQXyOEQ== X-Google-Smtp-Source: AGHT+IHnnbXv7LLoQQuo5IERPmQ1aDbHfWs5esMUO9nvMTULeZpbAQsvNcJD7PAXZFLGmSXlcp3hjA== X-Received: by 2002:a05:6a00:1385:b0:6d9:bf50:196e with SMTP id t5-20020a056a00138500b006d9bf50196emr7531070pfg.19.1705970761998; Mon, 22 Jan 2024 16:46:01 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id r5-20020aa78b85000000b006dbca81cc36sm5095359pfd.188.2024.01.22.16.45.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 16:45:57 -0800 (PST) From: Kees Cook To: linux-hardening@vger.kernel.org Cc: Kees Cook , Santosh Shilimkar , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, "Gustavo A. R. Silva" , Bill Wendling , Justin Stitt , linux-kernel@vger.kernel.org Subject: [PATCH 29/82] rds: Refactor intentional wrap-around calculation Date: Mon, 22 Jan 2024 16:27:04 -0800 Message-Id: <20240123002814.1396804-29-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240122235208.work.748-kees@kernel.org> References: <20240122235208.work.748-kees@kernel.org> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2769; i=keescook@chromium.org; h=from:subject; bh=rhiNkfwcsBY8pN0Aj3OX3M7epOQG7vcAhg9hdXLwAek=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlrwgHOI22byaB9aq3JAA27hbl1bc2MNGKba4Qk /4yGoiLhCWJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZa8IBwAKCRCJcvTf3G3A JrEqD/9OlGCVGN2v0bgu7DOOkBDw0dRbBn44WXpE64TTI2iaigc2NjR7rlxLD88o/toMj5HP2e8 +KNhHHhwpn/78Xvy5Fu7OSRDC9Srz2FSdC3GIXCLEy3jHqWqKwpl8s89sAkiyFxj+oaSSd2hp1Z yyDFk5tnp4WFMby/w16JX9RJaUhf0Pac+SlpfX6LIhCtEDu16Ym3Zfy8+niKDzyKzgFnik3iBMB VlX0qsJgWtq/F5TyYJsdRkzQJiC6uqDjRDOmIrgGbtONP4N3x7eTO2RPGiq6W6sD6wqCCTfno+I TOyJBsebkoEC/gOponWRkhVaYuIKk76Rd+mpLbYKMeJ9sXs4c3jKafZerrydOpptCgnp1tAjfY0 ubJ/wJ50cALOah3qX7E1BFVlS8g/8Cqst3G86qmJ+jErESB4X+ju8cl4kzQJrDdmKNVd/8RAdsb wNPuvNZwa3p4pqL+xtVz52yuC0AAOm1Ac9cbprphOD3okeaOY4R3ObpX9GV0e/990fYjXWl4bXk aTpyUseDCo88l0yQhgdSuHpJyQLFga2P8uROjArZRuSEBD9HUQ3LrxEC/e8Ns++bdkQ4Yu2PgDo Dty8RA9kx6885engKkChV3U1u51xbiNowBg4oJDE5G4q+gYIHu+fcsm6+5uoTqYHDGNdkR/t2tx b/RZj59k1eBK/EQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 In an effort to separate intentional arithmetic wrap-around from unexpected wrap-around, we need to refactor places that depend on this kind of math. One of the most common code patterns of this is: VAR + value < VAR Notably, this is considered "undefined behavior" for signed and pointer types, which the kernel works around by using the -fno-strict-overflow option in the build[1] (which used to just be -fwrapv). Regardless, we want to get the kernel source to the position where we can meaningfully instrument arithmetic wrap-around conditions and catch them when they are unexpected, regardless of whether they are signed[2], unsigned[3], or pointer[4] types. Refactor open-coded unsigned wrap-around addition test to use check_add_overflow(), retaining the result for later usage (which removes the redundant open-coded addition). This paves the way to enabling the unsigned wrap-around sanitizer[2] in the future. Link: https://git.kernel.org/linus/68df3755e383e6fecf2354a67b08f92f18536594 [1] Link: https://github.com/KSPP/linux/issues/26 [2] Link: https://github.com/KSPP/linux/issues/27 [3] Link: https://github.com/KSPP/linux/issues/344 [4] Cc: Santosh Shilimkar Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: netdev@vger.kernel.org Cc: linux-rdma@vger.kernel.org Cc: rds-devel@oss.oracle.com Signed-off-by: Kees Cook --- net/rds/info.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/rds/info.c b/net/rds/info.c index b6b46a8214a0..87b35d07ce04 100644 --- a/net/rds/info.c +++ b/net/rds/info.c @@ -163,6 +163,7 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, unsigned long nr_pages = 0; unsigned long start; rds_info_func func; + unsigned long sum; struct page **pages = NULL; int ret; int len; @@ -175,7 +176,8 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, /* check for all kinds of wrapping and the like */ start = (unsigned long)optval; - if (len < 0 || len > INT_MAX - PAGE_SIZE + 1 || start + len < start) { + if (len < 0 || len > INT_MAX - PAGE_SIZE + 1 || + check_add_overflow(start, len, &sum)) { ret = -EINVAL; goto out; } @@ -184,7 +186,7 @@ int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval, if (len == 0) goto call_func; - nr_pages = (PAGE_ALIGN(start + len) - (start & PAGE_MASK)) + nr_pages = (PAGE_ALIGN(sum) - (start & PAGE_MASK)) >> PAGE_SHIFT; pages = kmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);